Conversations With Prostate Cancer Experts

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Dr. Matthew Cooperberg is an Associate Professor of Urology and the Helen Diller Family Chair in Urology at the University of California, San Francisco. He is keenly interested in risk-stratifying prostate cancer to better match treatments to those most likely to benefit.

Prostatepedia spoke with Dr. Cooperberg recently about the role imaging plays in prostate cancer treatment.

Are there any other imaging techniques on the horizon that may replace the MRI?

Dr. Cooperberg: There is a lot of excitement for what will be the next-generation MR spectroscopy based on hyperpolarized Carbon-13 imaging. This is next-generation MR imaging in which we can essentially watch metabolic pathways unfold in real time at the millimeter level. That’s going to be incredible. This technology was developed by John Kurhanewicz at UCSF and is in late phase testing now. A few of these machines exist so far around the world; this may really be a game changer.

Technologies for next-generation ultrasound may also be able to yield a very high-resolution picture. These technologies have to be studied carefully head-to-head. It may bear out that better ultrasound technology will prove more cost-effective and easier on the patient than MRI, which requires separate visits, separate costs, and multiple physicians. Plus, MR is competing—especially when we talk about active surveillance—with blood, urine, and tissue biomarkers. Should a surveillance candidate who is on the edge get an MRI, a Decipher test, or both?

Would you use multiple tools or just one?

Dr. Cooperberg: Potentially multiple, but if everyone uses multiple tools, the cost increases exponentially. We don’t always know what to do with conflicting information. If you have a reassuring MRI and a concerning Decipher score, what do you do? If you have a high biomarker score and the MRI still doesn’t show anything, what do you do? These are challenging questions.

From a research standpoint, this is what makes it fun. But for the man on the ground, there is a lot of confusion. It’s part of the reason that I’m skeptical about how aggressively a number of these tests are marketed in the prostate cancer community.

You mean how tests like Decipher are marketed in the community?

Dr. Cooperberg: And MRI. It’s all in the same category. When I give a talk on MRI, I consider it to be a novel biomarker. It faces all the same challenges and has to play by all the same rules as Polaris or Decipher. You’ve got to prove that it’s going to give you better information than you can get from the basic clinical assessment. You’ve got to prove it’s going to help you make a better decision. And you’ve got to prove that it gets better outcomes, just like the biomarkers. Just as we’re not quite there with the biomarkers, we’re not quite there with MRI.

Imaging is important for newly diagnosed prostate cancer patients who may or may not have localized disease, and it’s especially important for advanced prostate cancer patients, whether they continue to be androgen sensitive or have developed some level of androgen resistance. For earlier stages of disease, there has been a lot of interest regarding multiparametric MRI. Nonetheless, the efficacy of multiparametric MRI is limited by the expertise of the interpreting radiologist. The fusion technology software championed by several of the academic centers has been rolled out without consistency within the community. For some practices, it was adopted due to marketplace competition and the device developers’ promotions. Companies that develop multiparametric fusion technology have not made a significant contribution to the advancement of urologic and radiologic educational needs. That said, some groups incorporated dedicated specialists within their practice to train for high-quality multiparametric fusion-based biopsies. Purchasing the newest promising technology without ensuring a framework to optimize clinical results will lead to poor implementation. In the United States, MRI is still mostly recommended for patients who have had a negative prostate biopsy, but due to age, PSA kinetics, or rectal examination, there is still a concern of possible malignant disease that was missed on the first biopsy. MRI is most uniformly accepted for additional information when evaluating patients for the need for a second biopsy. MRI will no doubt have an ongoing role in the active surveillance population. MRI will no doubt have an eventual role in decision making for possible first biopsies.

There has been a lot of very good, evidence-based literature coming from European countries that suggests that whole-body MRI, with the right software protocol, is exceptionally helpful in evaluating metastatic disease. Unfortunately, in the United States, this protocol takes 45 to 60 minutes to accomplish, and unfortunately, translates to a challenging economic utility model for the MRI efficiency from an administrator perspective. There are many interesting and promising blood-, tissue, and urine-based markers, genomic assays, and additional imaging techniques, which require ongoing trials to determine how best to use them for the most efficient value-based care model. No single test—MRI or any other blood-, tissue-, or urine-based marker—is perfect. Eventually, we will hopefully develop a cost-effective algorithm that combines a panel of all the different biomarkers. MRI is part of that discussion, but we don’t have that sorted out currently. There have been multiple PET scan technologies developed in the last several years that have been assessed for improved potential sensitivity and specificity, and ultimately, to improve the accuracy of the data that shows cancer spread and its location. MRI and Axumin PET scanshave been approved for advanced prostate cancer patients. There have been other PET scans such as FDG, C-11 Acetate, C-11 Choline, sodium fluoride, which have not received widespread reimbursement approvals nor widespread accessibility. There is also no consensus recommendation for these technologies.